Method and apparatus for fluid mixing and spraying



All@ 18, 1953 Rv. J. MILLER 2,649,333

METHOD AND APPARATUS FOR FLUID MIXING' AND SPRAYING Filed Feb. 21, 19502 Sheets-Sheet 1 Aug. 1s, 1.953

51am-LODv AND APPARATUS .FOR FLUID. MIXING AND SPRAYING Filed Feb. 21,195o 2 Sheets-Sheet 2 INVENTOR.

f W M MA J. a M. m W

Patented Aug. 18, 1953 METHOD AND APPARATUS FOR, FLUID MIXING ANDSPRAYING Raymond J. Miller, Detroit, Mich., assigner to Dearborn MotorsCorporation, Highland Park,

Mich., a, corporation of Delaware Application February 21, 1950, SerialNo. 145,528

14 Claims. l

This invention relates to improved methods and apparatus for mixing andspraying uids and, while not limited thereto, finds particularapplication in the eld of agricultural spraying.

The employment of sprays in agriculture has increased tremendously inthe past few years. While the use of sprays has been quite common inorchard culture, large new elds of application have been opened by therecent development of very effective spray concentrates for killingvarious types of noxious weeds, for defoliation and for the destructionof insects.

With few exceptions, all agricultural sprays employ Water as the primaryor carrier fluid and require the injection and thorough mixture in theprimary fluid of a proportional quantity of spray concentrate. However,a number of problems have been encountered in agricultural spraying. Inthe rst place, the desired ratio of concentrate or toxic fluid to thecarrier fluid is generally quite small, so that great difficulty hasbeen encountered in properly metering the amount of toxic fluid to beintroduced into a given quantity of the carrier fluid, Secondly, many ofthe toxic fluids are not readily dispersible in the carrier fluid andhence require lcontinuous agitation of the fluid mixture to maintain adispersion of the toxic fluid throughout the carrier fluid. Heretofore,such agitation has generally been accomplished by utilizing a largercapacity pump than is actually required for discharge of the mixed sprayand employing the excess capacity of the pump solely for recirculatingand agitating the iiuid mixture carried in the tank or similar containerof the spraying apparatus. Lastly, and most important from thestandpoint of the farmer user, is the fact that once the spraying righas been employed for spraying a particular fluid concentrate, it is anextremely diiicult job to clean the spray rig suiiiciently to insurethat its subsequent use with another type of spray concentrate will notbe contaminated by the original spray concentrate. This is aparticularly annoying problem when a weed killing type of spray has beeninitially used in the spray rig and then it is desired to use the samerig to spray an insect destroying concentrate on a leafy type vegetablecrop. It often happens that the small residue of the weed killingconcentrates remaining in the spray -rig, even after extensive cleaningattempts, will produce sufficient contamination of the latter spray toseriously harm the crop to which the second spray is applied.

Accordingly, this invention embodies Several new concepts in bothmethods and apparatus for proportionally mixing fluids and for sprayingthe resultant fiuid mixture, with the object of overcoming all of theabove mentioned problems and improving the effectiveness and operationalfacility of agricultural spraying, while at the same time reducing thesize, cost and capacity of the spraying apparatus.

One basic concept and objective of this invention lies in the provisionof a novel method and apparatus for eiiecting the proportional mixing ofthe toxic iiuid in the carrier uid at a point adjacent to the dischargenozzle of the spraying rig, thereby eliminating the need for excess pumpcapacity for recirculating mixed uids for agitation purposes.

A further basic concept and objective of this invention lies in theconducting of the carrier fiuid and the toxic fluids by separateconduits to a proportional mixing device located adjacent to thedischarge nozzle and in providing quickly detachable connections of theproportional mixing device and the toxic fluid conduit to the remainderof the spraying rig so that these elements may be quickly and easilyremoved and replaced by identical elements Whenever the rig is convertedfrom one type of spraying operation to another. In this manner, thenecessity for cleaning the spraying rig is eliminated, as the onlycontaminated portions of the spraying rig are removed and replaced.

Still another basic concept and objective of this invention lies in themethod and apparatus for effecting accurate proportional mixing of twofluids by utilization of a porous mass of sintered particles, andparticularly sintered metal particles, as a barrier between the twofluids to be mixed, and producing a differential pressure between suchtwo fluids. This invention provides the discovery that the rate of fluidiiow through a porous mass of sintered particles is a direct andpredictable function of the porosity of such mass, the viscosity of thefluids, and the pressure differential existing between one surface ofthe mass contacted by the fluid and any other surface. It is aparticular object of this invention to apply this discovery to the artof spraying, and parv ticularly agricultural spraying, through theutilization of a mass of sintered metal particles as the device foreffecting the proportional mixing of a small quantity of toxic fluid ina much larger quantity of a carrier fluid.

Other particular objects of this invention are: the provision of simple,inexpensive nozzle members for spraying rigs which effect both theproportional mixing of a toxic fluid in a carrier Huid and the dischargeof the thoroughly mixed fluid in a spray form suitable for directapplication to plants, live stock, or the like; the provision ofinexpensive, rugged apparatus, suitable for mounting on a mobile orportable spraying rig, for producing the required differential pressurebetween the carrier fluid and the toxic fluid to effect the meteredmixing of such fluids by a sintered metal mass; and lastly, theprovision of a spraying rig wherein a minimum of partsare contaminatedby the toxic fluid and all such contaminated parts are quicklydetachably mounted to the remainder of the rig to permit theirconvenient replacement by like parts to convert the rig from one type ofspray to another without cleaning operations.

The specic nature of this invention, as well as other objects andadvantages thereof, will become apparent to those skilled in the artfrom the following detailed description, taken in conjunction with theattached sheet of drawings on which, by way of preferred example onlyare illustrated several embodiments of this invention.

On the drawings:

Figure 1 is a side elevational view of a portion of a Spray boomembodying a nozzle and mixing device constructed in accordance with thisinvention.

Figure 2 is a sectional view taken on the plane 2-2 of Figure 1.

Figure 3 is a sectional View taken on the plane 3-3 of Figure 1.

Figure 4 is a sectional view of a modified construction of combinednozzle and mixing devices embodying this invention.

Figure 5 is a composite View illustrating various modified shapes ofsintered particle masses usable as proportional fluid mixing devices.

Figure 6 is an elevational view of a portion of a spray boom, partly insection, employing a further modification of a combined nozzle andmixing device embodying this invention.

Figure 7 is an elevational view, shown partly in section, of a modifiedmanner of securing a combined metering and spraying nozzle to the sprayboom.

Figure 8 is a sectional view taken on the plane 8 8 of Figure '7.

Figure 9 is a schematic View of a hydraulic system for producing aconstant pressure differential between the primary uid and the toxicfluid supplied to the spraying rig.

Figure 10 is a schematic view illustrating a modied hydraulic system forproducing a constant pressure differential between the primary fluid andthe toxic fluid supplied to the spraying rig.

As shown on the drawings:

Referring to Figures 1 through 3, the numeral I0 indicates a portion ofa spray boom or similar form of conduit which is commonly employed toconduct the primary uid of the spray, generally water, to one or morepoints of discharge. A combined mixing and spraying nozzle II embodyingthis invention is suitably secured to the boom or conduit lil adjacentto an aperture Ilia in the wall of such conduit. The mixing nozzle IIincorporates a tubular mounting portion I2 which has one end face 12athereof arcuately shaped to snugly conform to the surface of the boomIl) and is suitably secured to the boom I0 in any desired manner, as foreX- ample, by cementing, welding or brazing. The

i bore I2b of the tubular base portion I2 is in alignment with theaperture lila in the wall of the boom I 0. The outer axial end oftubular base portion I2 has a reduced diameter cylindrical portion I2Cformed thereon. A hollow nozzle body I3 has a counterbore I3a whichpermits it to be snugly mounted'on cylindrical surface I2c and an O-ringseal I4 is suitably mounted intermediate tubular member I2 and nozzlebody member I3 to prevent iiuid leakage therebetween. Suitable means areprovided to detachably secure nozzle body i3 on mounting portion I2 aswill be later described. Nozzle body member I3 defines an axial bore I3bextending therethrough and threaded at its outer end to receive a nozzlemember I5. Nozzle member I5 Vhas a bore I5a which is suitably shaped soas to produce a spray discharge of fluids applied thereto under moderatepressures.

A secondary counterbore I3c is formed intermediate the bore |313 and theoutermost counterbore I3a and this counterbore serves to position anannular porous mass IB of sintered particles which functions as aproportional mixing device. The mass I6 may utilize any porous sinteredcomposition, but preferably is formed of sintered, corrosive resistant,metal particles. As is well known in that art, the size of the metalparticles forming the mass I6 determines the relative porosity of themass I6, and I have discovered that the amount of fluid transmittedthrough such a sintered mass is a direct function of the porosity of themass and of the fluid pressure differential.

As was previously indicated, one axial face of the annular mass I6 seatssnugly in the base of the secondary counterbore I3b of the nozzle bodyI3. The other axial face of the mass I6 snugly engages the outer end ofthe tubular member I2 in sealing relationship. If desired, thecooperating surfaces of the mass I6 and the tubular member I2 may bebevelled as indicated at I6a. The bore Ib of the mass IB is in directfluid communication with the interior of the boom Ill as well as withthe nozzle defining bore I5a of the nozzle element I5. The outercylindrical surface ISC of the sintered mass I6 is spaced inwardly fromthe walls of the outermost counterbore |3a and thus defines an annularchamber I3d. A pipe-like radial protuberance I3e is integrally formed onthe nozzle body I3 and its bore I3f communicates with the annularchamber I3d. A conduit I'I is detachably connected to the protuberanceI3e in any suitable manner, for example, the conduit I`I may be formedof flexible plastic or rubber-like material which is expanded to tsnugly over such protuberance.

One of the fundamental concepts of this in.- vention is the utilizationof a mass of sintered particles as a device for effecting a proportionalmixing of the `toxic fluid'of lthe spray with the carrier fluid.Referring particularly to the apparatus of this invention shown inFigures 1 through 3, the carrier fluid, generally water, may be suppliedunder pressure by any conventional apparatus to the interior of the boomconduit I0. The toxic fluid may likewise be supplied under pressure tothe annular chamber I3d, however, the pressure of the toxic fluid issomewhat higher than that of the carrier fluid so that a fluid pressuredifferential exists between the surfaces of the sintered mass I6 whichare respectively exposed to the carrier fluid and to the toxic fluid.Under these conditions, a metered amount of toxic fluid will seepthrough the sintered mass I6 and emerge on those surfaces of thesintered in the carrier fluid flowing through the bore I 6bv and thefluid mixture will be immediately discharged in spray form through thebore I5a of the nozzle insert I 5.

Many tests of apparatus embodying this invention clearly establish thefact that the rate of flow of the toxic fluid through the mass ofsintered particles is determined solely by the porosity of such mass,which is constant, the viscosities of the fluids, which are alsoconstant for a definite temperature, and by the fluid pressuredifferential existing across the surfaces of the mass. Hence, so long asa substantially uniform fluid pressure differential is maintainedbetween the carrier fluid in the boom I Il and the toxic fluid at itspoint of entry into the annular chamber I3d, the rate of flow of toxicfluid into the carrier fluid will be substantially constant and can beconveniently selected by control of the pressure differential to producethe desired proportions in the mixture of the toxic fluid in the carrierfluid.

It should be particularly noted that with the described apparatus, noportion of the boom proper, or any of the cooperating fluid system whichsupplies the carrier fluid to the boom, is in any manner contaminated bythe toxic fluid. Hence, if the combined nozzle and mixing device II andthe toxic fluid conduit I'I are constructed to be quickly detachablefrom the boom I0, the user may eliminate the need for cleaning his sprayrig when shifting from one type of spray to another through the verysimple expedient of substituting a new set of mixing nozzles II andtoxic fluid conduits I'I.

To facilitate such replacement, the modification of this invention shownin Figures 1 through 3 employs a spring catch I8 which serves todetachably secure the nozzle body member I3 in assembly on the tubularbody element I2. The spring catch I8 may be conveniently formed ofspring wire and is bent into a generally U-shaped configuration. TheWire ends I8a are pivotally secured in suitable radial aperturesprovided inv the exterior of tubular member I2 and the intermediate armportions of the wire I8 are formed into loops I8b which respectivelycooperate with projecting lugs I9 formed on the exterior of nozzle bodymember I 3. Hence, al1 of the toxic fluid contaminated portions of themixing nozzle II may be removed by releasing the wire latch I8 andremoving the nozzle body I3, the connected toxic fluid conduit I'I andthe sintered mass I6. Obviously, in most nozzle spraying applications aplurality of such mixing nozzles II are provided on the spray boom I0and all of such nozzles may be conveniently replaced in the describedmanner.

From the foregoing description, it will be apparent that this inventionutilizes two basic method concepts in the mixing and spraying of fluids.First, there is the concept of positioning the fluid mixing and meteringdevice closely adjacent the discharge nozzle of the spray and effectingthe proportional mixing of the toxic fluid with the carrier fluidimmediately before the discharge of the mixed fluids as a spray. Suchmethod permits the pumping capacity to be limited to that necessary toproduce the desired rate of discharge of the carrier fluid, andcompletely eliminates ther necessity for substantial additional pumpcapacity for rec1rculat1on and agitation purposes which has beeninherent in all prior spraying systems. Furthermore, the `employment-ofa separate fluid system'to supply the toxic fluid to the mixing device,coupled with the detachable connection of the mixing device to the sprayboom at the point of discharge of the spray, eliminates the necessityforcleaning the entire spray rig and permits the user to quickly andconveniently shift from one type of spray to another through the simpleexpedient of replacing the mixing nozzle and the toxic fluid supplysystem. The second method embodiedv in the apparatus heretoforedescribed is the uti,- lization of a mass of sintered particles as aproportional mixing device for two fluids. In broadest terms, it will beseen that such method simply involves the disposing of a mass of poroussintered particles between two fluids to be mixed and the production ofa selected pressure differential between such two fluids which willresult in a metered flow of the higher pressured fluid into the lowerypressured fluid, the rate of such flow being constant for any selectedpressure differential and selected porosity of the mass of sinteredmaterial. The utilization of such method completely eliminates theheretofore required tedious measuring of the quantities of carrierfluids and toxic fluids introduced into the spraying apparatus. v

An additional feature of this invention is the discovery that a morethorough dispersion of a toxic fluid in a carrier fluid may beconveniently produced by forcing the mixed fluids through a porousbarrier of sintered particles. Referring particularly to themodification illustrated in Figure 4, it will be noted that theconstruction of the mixing nozzle is very similar to the modiflcation ofFigures 1 through 3 with the exception of the nozzle body. In themodification of Figure 4, the nozzle body 20 is of somewhat increasedlength and includes not only a primary counterbore 20a for mounting onthe tubular body I2 and a secondary counterbore 20h for mounting theannular mass I6 of sintered particles, but is further provided with atertiary counterbore 20c which supports a solid porous mass 2I formed ofsintered particles directly in the path of fluid flow through the mixingnozzle.' Also, the outer end of nozzle body member 20 is suitably boredto define a nozzle orifice 20d which is an alternative arrangement tothe threading in of a separate nozzle member as in the modification ofFigures l through 3.

With the described construction of Figure 4, the proportional mixing ofthe toxic fluid in the carrier fluid isagain accomplished by the annularmass I6 of sintered particles. The mixed fluids are then forced throughthe porous mass 2I of sintered particles. Obviously, the sinteredparticles of mass 2l are in general of substantially greater size thenthose of the metering mass I6 so as to not require an excessive pressureto force the mixed fluids through the mass 2I with sufficient velocityto produce the desired spray discharge. In any event, the passing of themixed fluid through a porous barrier mass 2I vof sintered particles hasthe very desirable effectof producing a more completey dispersion of thetoxic fluid throughout the carrier fluid.

It is therefore apparent that a single porousy mass of sinteredparticles might be conveniently employed to produce both theproportional mixing and the dispersion functions. Furthermore, bysuitably shaping the surfaces of such porous mass from which the mixedfluids are discharged,

the porous mass maybe employed toattain desired fluid flowcharacteristics to facilitate the formation of the discharge spray.Referring particularly to Figure 5, there is illustrated a plurality ofshapes in Which the porous sintered particle mass may conveniently beformed to perform the combined functions of proportional mixing offluids, intimate dispersion of one fluid in another, and formation offluid flow characteristics for the mixed fluid which will facilitate theproduction of a fine discharge spray. The six modifications have beenlabeled A through G respectively, and in each case the surface of thesintered mass `to which the toxic fluid is applied has been indicated bythe letter 'I, the surface to which the carrier or primary fluid isapplied is indicated by the letter 13, and the discharge or outletsurface or area has been indicated by the letter 0.

Referring back again to the modification of Figure 4, it is alsoapparent that the provision of the barrier mass 2i of sintered particlesin the mixing nozzle will perform the additional desirable function ofsubstantially eliminating dripping of the mixed fluids from the nozzlewhen the fluid pressure has been out ofl from the boom conduit I and thetoxic fluid conduit I'I. In existing sprayer constructions, the drippingfrom the nozzles continues until all of the fluid contained in the boomleaks out. When sprays are employed which can be detrimental tovegetation or crops, great care has to be taken in the path chosen bythe operator of the spraying rig to preclude the accidental damage ofsuch crops by the drippings from the boom. Since it is a function of theporous mass of sintered particles that some pressure differential isrequired to force fluids therethrough, it is apparent that the barriermass 2I will produce a substantially immediate cut-off of fluid flowwhenever the supply of pressured fluid to the boom I0 and the toxicfluid conduit I'I is interrupted.

Referring to Figure 6, a modification of this invention is shown whichconveniently permits any desired number of mixing nozzle units to beassembled into a spray boom of any desired length. The nozzle bodyportion 22 employed in this modification is of substantially similarconstruction to that shown in the modification of Figure 4, with theexception that a pair of hollow protuberances 22e are provided indiametrically opposed relationship, each of Which define bores 22 fcommunicating with the annular chamber 22d surrounding the annularporous mass I6 of sintered particles. Hence, toxic fluid may be suppliedto one protuberance 22e by the toxic fluid conduit I1 and additionallysupplied to the next mixing nozzle unit (not shown) by a continuationconduit I'I' connected to the other protuberance 22e.

A mounting element 23 is provided for effecting the mounting of thenozzle body portion 22 on the boom and in communication with the fluidconduit defined by the boom. The mounting element 23 defines a maincylindrical bore 23a extending therethrough at right angles to a nozzlesupply bore 23h. At each end of the main bore 23a., the mounting element23 is provided With cylindrical surfaces 23e which respectively snuglymount pipe-like sections 24, which sections when assembled dene thespraying boom. Accordingly, a spraying boom of any desired length may beconveniently assembled merely by adding an additional boom section 24,toxic fluid conduit I'I, a nozzle mounting element 23, and a mixingnozzle unit 22. It Will be understood that suitable connections are madeto one of the boom sections 24 for supplying the carrier uid theretounder the required pressure and, likewise, suitable connections areAmade to one of the toxic fluid conduit sections I1 for supplying toxicfluid thereto at the required pressure differential above the pressureof the carrier fluid.

Mounting element 23 is further provided with a cylindrical flangeY 23dsurrounding the open end of the nozzle supply bore 23h and such flangemounts the nozzle body 22 in the same manner as in the modificationspreviously described. If desired, the open end of the nozzle supply bore23h may be counterbored as indicated at 23e and a filtering disc 25 maybe snugly seated in the base of such counterbore. Filtering disc 25 mayalso comprise a porous mass of sintered particles whoseporosity isselected to produce effective filtering of the carrier fluid to preventlarge foreign particles from being passed into the mixing nozzle, butwhich will not substantially reduce the pressure of the carrier fluidpassing therethrough.

Referring to Figures 7 and 8, there is shown a modified arrangement forattaching a mixing nozzle unit I I, similar to that shown in themodiflcation of Figures 1 through 3, to the spray boom I0. Instead ofthe tubular mounting unit I2 being welded to the supply boom I0, it ismerely suitably shaped so as to snugly engage the surface of such boomand is detachably clamped into engagement with the boom I0 by a clampingunit comprising a pair of tong members 30 having inturned end portions30a engaged in suitable recesses on the exterior of the tubular mountingportion I2 and bight portions clamped to a block 3| by an appropriatelyshaped stamping 32. A thumb screw 33 is threaded through a suitableaperture in block 3I and contacts the Wall of boom I0 at a pointopposite the connection of the mixing nozzle II thereto. Tightening ofthe thumb screw 33 will obviously draw the tubular mounting portion I2into snug engagement With the boom I0.

In all of the modifications heretofore described, it was contemplatedthat suitable hydraulic mechanism Would be provided for supplying boththe carrier fluid and the toxic fluid under pressure to the mixingnozzle units and that the toxic fluid would be maintained at a selectedpressure differential above the pressure of the carrier fluid. While anyconventional form of hydraulic system may be employed to produce thedesired pressures and pressure differential, I have schematicallyillustrated in Figures 9 and 10 two hydraulic arrangements of unusuallysimple construction for accomplishing such functions.

Referring to Figure 9, the numeral 4l) indicates a suitable container ortank for carrier fluid which, as mentioned above, Will generally beWater. Such fluid is pressured by a pump 4I and supplied under pressureto a container 42 which has a quantity of air trapped therein. Thepressure of carrier fluid in container 42 is maintained at a selectedValue by an adjustable relief valve 43 which bleeds back a sufficientquantity of the pressured fluid to the primary container 40 to maintainthe selected pressure level in the secondary container 42. An outletconduit 44 is connected to the secondary container 42 and supplies thepressured carrier fluid to the spray boom through a suitable shut-offValve 45.

The top end of secondary container 42 wherein the air is trapped underpressure is connected Vbya conduit 46 to one side of pressuredifferential 41d.l lThe difference in area of the two ends 4'lc and 41dis exactly proportional to the pressure differential that it is desiredto maintain between the toxic fluid and the carrier fluid. The large end41e of the regulating piston 4lb is exposed to the pressure of theprimary fluid through conduit 46. The toxic fluid is mounted in acontainer 48 which has an outlet conduit 49 at its bottom end connectedto the toxic fluid conduits |1 of the mixing nozzles through a suitableshutoff valve 50. A quantity of air is trapped in the top of toxic fluidcontainer 48. The pressure of such trapped air, and hence the pressureof the toxic fluid, is applied to the small diameter end 47d of theregulating piston 4lb through a conduit connected to the top end oftoxic fluid con- `tainer 48, a quick disconnect coupling 52, and aconduit 53. Air pressure is supplied to the toxic fluid container 48from an air pump 54 which is connected to a medial portion of theregulating valve cylinder 41a by a conduit 55. An adjustable reliefvalve 56 maintains the output pressure of pump 54 at a selected value. Amedial portion of the piston 4'Ib is annularly relieved as indicated at41e and such relieved portion is located in the vicinity of the airpressure conduit 55. Opposite the air pressure conduit 55, a conduit 57is connected to the cylinder 47a and connects with the top of toxicfluid container 48 through a quick disconnect coupling 58 and conduit59.

; From the foregoing description, it is apparent that the regulatingvalve unit 4l will maintain a pressure in the toxic fluid container 48which -is at a selected differential labove the pressure of the carrierfluid. Hence, the proportional mixing of the toxic fluid into thecarrier fluid will be accomplished by the sintered metal masses in thenozzles in the manner heretofore described. It

.should be particularly noted that the toxic fluid container 48 isdetachably connected to the re- .mainder of the hydraulic system by thequick disnozzles and the toxic fluid conduit and replaced by identicalelements. Hence, there is no need for cleaning any portion of the systemsupplying the carrier fluid. Likewise, it is unnecessary to clean theremovable portions of the spray rig which have been contaminated by aparticular toxic fluid as those portions may be stored until thatparticular toxic fluid spray is desired to be used again.

In the hydraulic system shown schematically in Figure 10, the requiredpressure differential between the toxic and carrier fluids may beproduced by a vsingle pump. Here again a container or tank 40 isprovided for the carrier fluid andv such fluid is pressured by a pump 4|and regulated by an adjustable relief valve 43. A toxic vfluid container60 is provided having a conduit .6| connected to its bottom end andconnecting with the toxic fluid conduit of the mixing nozzles through ashut-off valve 62. The toxic fluid container 60 has a detachable cover63 which may be sealed thereto by a clamping unit 64. The

" toxic fluid contained within container 60 is sub- Yduit I6 throughshut-off valve 45.

l0 jected to the full outlet pressure of the pump 4| by a flexiblebladder which is disposed within the chamber 60 and has its interiorconnected to the outlet pressure vof pump 4| by a conduit 66. To supplythe carrier fluid to the mixing nozzles,

, a reducing and regulating valve 4l, similar in all respects to thereducing and regulating valve 41 described in the modification of Figure9, is connected intermediate the pressure side of pump 4| and a conduit44 which leads to the boom con- In this instance, the small area end 41dof the regulating piston 41h is exposed to the outlet pressure of pump4| through a conduit 6l, while the large diameter end 47C of regulatingpiston 41h is exposed to the carrier fluid pressure through a conduitconnection 66 with the carrier fluid discharge conduit 44. The conduit44 is connected the piston, while a conduit 69 connects the pressureside of pump 4| to the medial portion of the cylinder 41a directlyopposite the connection of conduit 44 thereto. Hence, the carrier fluidis supplied to the boom at a selected pressure below the pressure towhich the toxic fluid is supplied thereto. Furthermore, no portion ofthe hydraulic mechanism with which the carrier fluid comes in contact iscontaminated by the toxic uid and the hydraulic system may be convertedto spraying a different toxic fluid merely by replacement of the toxicfluid container 60.

From the foregoing description, it is apparent that this inventionprovides novel and improved methods and apparatus for fluid mixing andspraying which will not only greatly simplify agricultural types ofspraying equipment, but which will provide a degree of performance andease of handling which has in no manner been possible with methods andAdevices heretofore known.

It will, of course, be understood that various details of constructionand process may be varied through a wide range without departing fromthe principles of this invention and it is, therefore,

not the purpose to limit the patent granted hereon otherwise thannecessitated by the scope of the appended claims.

I claim:

1. A spraying and mixing nozzle comprising a hollow body having a boreextending therethrough, a porous mass of sintered particles mounted insaid bore and cooperating with a portion of said bore to define a fluidchamber separated from the remainder of said bore, means for connectingone end of said bore to a source of pressured primary fluid, and meansfor connecting said fluid chamber to a source of secondary fluidpressured to a higher value than said primary fluid, the pressuredifferential between said primary and secondary fluids beingproportioned to the porosity of said porous mass, whereby a desiredproportional mixture of said fluids is discharged from the other end ofsaid bore.

2. -A spraying and mixing nozzle comprising a hollow body member havinga bore extending therethrough, means in one end of said bore defining aspray producing orifice, a pair of counterbores formed in the other endof said bore, an

annular porous mass of sintered particles seated nular chamber to asource of toxic iluid pressured to a higher value than said primaryfluid, the pressure differential lbetween said carrier and toxic iiuidsbeing proportioned to the porosity `of said 4-porous mass, whereby ametered mixture of said toxic fluid in said carrier fluid is produced.

3. A spraying and mixing nozzle comprising a hollow body member having abore extending therethrough, means in one end of said bore delining aspray producing oriilce, a plurality of successive counterbores formedin the other end of said bore, a solid porous mass of sintered particles-seated in the first and smallest of said counterbores, an annularporous mass of sintered particles seated in a second counterbore and cov'operating with a third counterbore tol define an 4. A spraying andmixing nozzle comprisingv a i hollow body member having a bore extendingtherethrough, means in one end of said bore delining a -spray producingoriiice, a plurality of vsuccessive counterbores Aformed in the Votherend of said bore, an annular lporous mass of sintered particles Yseatedin the first and smallest of said counter-bores and-projecting axiallyinto the second counterbore, a hollow mounting element `having tubularportion snugly insertable in said second counterbore, said annularporous mass `cooperating -with said second co-unterbore and -saidtubular portion to denne an annular chamber separate from said bore,means for connecting said hollow mounting element to a source ofVpressuredcarrier fluid, and means for connect-ing said lannular chamberto a source of-toxic fluid pressured-to a higher 'Value than saidprimary `uid, the pressure differential Abetween said carrior`andtoxicii-uids being proportioned tothe lporosity of vsaid porous mass,'whereby a metered mixture of said toxic fluid in sa-idl carrierfluid'isproduced.

5. A spraying and-mixing nozzle comprising a `hollow .body member havinga bore `extending therethrough, means in Aone end of said -bore Vcle-'ning a spray producing orifice, a vplurality of successive'counterbores vformed in the other end "of said `bore, an vannularporousmass of sintered "particles'seated in the rstl and smallest'of saidVcounterbores Yand projecting axiallyl into thesec- 'ond counterbore, ahollow mounting element yhaving tubular portionsnugly insertable in saidsecond counterbore, means for Ydetachably `securing said body membertosaid mounting element, -said annular vporous mass cooperatingwith'said second counterbore and said tubular portionto dene an yannularchamber separate from'said bore; means for connecting said hollowmounting element to source of pressured carrier fluid, and means forconnecting said annular 'chamber to a 'source Yof toxic fluid pressuredto a higher value than said primary fluid, the pressure differentialVbetween said carrier and toxic fluids being proportioned to theporosity Jof said porousmass, whereby a metered mixture of said toxicfluid in 'said carrier iluid is produced.

6. A-device for proportionally mixing a'secondary fluid in a primaryfluid comprising means producing a flow of saidprimary'iluid, a-'porousmass of sintered particles, means for positioning said mass with onesurface thereofin contact with said iiow of primary fluid, andmeans-'for supplying said secondaryl fluid to another surface Aof saidmass remote from said one surface, said last mentioned means producing'ya pressure "of said-secondary iiuid on said mass in excess offthepressure of said primary-huid, the vvpressure Idifferential betweensaidy primary and secondary fluids being proportioned-to the porosityofsaid porous mass to produce a -desired meteredfflow of lsecondaryfluid vthrough said mass into'said primary uid.

'7. A device for proportionallymixing1 fluids comprising means dening afirst chamber for containing a primary fluid, means deiining a secondchamber for containingV a secondary fluid and a common wall vbetweensaid first and-'second chambers-having atleast a portion-thereofconsisting of a porous mass of sintered particles, and

means for maintaining a fluid pressure differential between said nrstand second chambers,the

pressure differential between said primary and secondary liuids beingproportioned to the porosity of said porous mass to-produce -a `desired`me- .tered flow of said secondary uid into said primary uid.

8. A device for :proportionally mixing fluids comprising a conduit,means for iiowinga primary iluid through said -conduit, ahollow Vmass ofsintered particles having its :bore communicating with said conduit,meansl directing'afsec'ondary fluid: into contact-with anexternalsurface`olP said hollow mass, and :means for `producing' apressure dierential rbetween said primaryfand secondary fluids, thepressure vdifferential between said primary and secondaryfluids Lbeingproportioned to the porosity Lof `said Aporous mass lto produceadesiredmetered flow of said secondary I fluid intosaidvprimary fluid.

.9. A fluid spraying -and'mixi-ng Vdev-ice comprising` a generallyconically Ashaped porous mass of sintered particles, said -rnass havinga concentrically disposedconic'al recess formed therein.

l0. A fluid .spraying and mixing device lcomprising afgenerally-conioally shaped porous'mass -of sinteredparticles,-said masshaving a concentrically disposed vconical recess formed therein, meansfor directingv a primary fluid under pressure into said recess, meansfor applying a secondary' iiuid t0 the external surface of said mass.and -means for maintaining a pressure differential between said 'primaryand secondary fluids.

l1. A device for spraying mixtures of atoxic fluid and a carrierfluid-comprising a iirst fluid rsystem for supplying said carrier fluidto a discharge opening, a'second'fiuid'system for supplying said toxicfluid :at a pressure greater than the discharge pressure of Said carrierfluid, a mass of sintered metal .particles associated'wlth said secondfluid system lso that said toxic fluid is applied under` pressure to onesurface of said mass, means for detac'hably connecting said mass to saidrst'iiuid system adjacent the discharge openingthereof and in'positionto have another surface thereof contacted by carrier fluid dischargedthrough `said discharge opening,- vthe 'pressure diierential betweenYsaid Vcarrier and toxic fluids being proportioned to the porosity ofsaid'porous'mass to produce' a metered flow 'of said toxic fluid intosaid carrier fluid.

12.`In a spraying device, fluid mixing. means, yindependent conduits forrespectively supplying a-carrier fluid and a toxic fluid'to'said fluidmixing means, a carrier fluid container, pump means for pressuring saidcarrier uid, a toxic fluid container communicating with the respectiveone of said conduits, a bladder in said toxic fluid container, meansconnecting the interior of said bladder to the pressure side of saidpump means, thereby pressuring the toxic iluid in said toxic fluidcontainer, and regulating valve means connected intermediate said pumpmeans and the other of said conduits for supplying pressured carrierfluid to said iluid mixing means at a selected pressure differentialrelative to said toxic fluid.

13. The method of proportionally mixing a primary fluid with a secondaryfluid ycomprising disposing the primary fluid adjacent to one surface ofa porous mass of sintered particles, disposing the secondary fluidadjacent to another surface of said mass remote from said one surface,and producing a higher pressure in said primary fluid than in saidsecondary fluid, the pressure differential between said primary andsecondary iluids being proportioned to the porosity of said porous massto produce a desired proportional mixing of said fluids.

14. In a sprayer having a pressured carrier fluid conduit and a hollownozzle body mounted on said conduit and in fluid communicationtherewith, the improvements comprising a nozzle tip structure mountableon said nozzle body, quick detachable means for securing said nozzle tipto said nozzle body in fluid tight relationship, said nozzle tip deninga rst fluid passage adapted ld to communicate with said hollow portionof said nozzle -body and a second passage separate from said rstpassage, a iuid mixing device disposed intermediate said first andsecond passages and providing the sole fluid communication between saidfirst and second passages, means for supplying pressured toxic fluid tosaid second passage, and means on said nozzle tip structure fordischarging the resulting mixed fluids in a spray form, wherebydetachment of said nozzle tip structure removes all elementscontaminated by toxic fluid from the sprayer.

RAYMOND J. MILLER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 815,713 Joslin Mar. 20, 1906 1,192,645 Koerting July 25, 19161,437,331 Alexander Nov. 28, 1922 1,727,294 Lennon Sept. 3, 19291,806,365 Paasche May 19, 1931 1,886,369 Bogart Nov. 8, 1932 2,178,539Hill et a1. Nov. 'ZJ 1939 2,359,386 Reinsch Oct. 3, 1944 2,500,816 GirdMar. 14, 1950 2,511,626 Einbecker June 13, 1950 2,515,394 Clarkson July18, 1950 FOREIGN PATENTS Number Country Date 528,619 Germany July 1,1931

